Method and device for adjusting data transmission rate in wireless communication system

ABSTRACT

The present invention relates to a method and apparatus for extending a data length of Bluetooth communication. A method of extending a data length of Bluetooth communication according to the present invention includes receiving a first message including information of a second device from the second device, transmitting a connection request message to the second device based on the first message, performing Bluetooth connection with the second device based on the connection request message, transmitting an extension request message which requests extension of a transmission data length and a reception data length through the connected Bluetooth, and receiving an extension response message in response to the request message through the connected Bluetooth, wherein the request message includes at least one of first maximum transmission data length information, first maximum reception data length information, first maximum transmission time information, or first maximum reception time information of the first device, and wherein the response message includes at least one of second maximum transmission data length information, second maximum reception data length information, second maximum transmission time information, or second maximum reception time information of the second device.

TECHNICAL FIELD

The present invention relates to a method and apparatus for adjustingthe data transmission rate in a wireless communication system, and moreparticularly, to a method and apparatus for enhancing the datatransmission rate in Bluetooth communication.

BACKGROUND ART

Bluetooth is a short-range wireless technology standard that maywirelessly connect various types of devices and allows them to exchangedata over short distances. To enable wireless communication between twodevices using Bluetooth communication, a user has to perform the processof discovering Bluetooth devices to communicate with and making aconnection request. As used herein, the term “device” refers to anappliance or equipment.

In this case, the user may discover a Bluetooth device according to aBluetooth communication method intended to be used with the Bluetoothdevice using the Bluetooth device, and then perform a connection withthe Bluetooth device.

The Bluetooth communication method may be divided into as a BR/EDRmethod and an LE method. The BR/EDR method may be called a BluetoothClassic method. The Bluetooth Classic method includes a Bluetoothtechnology led from Bluetooth 1.0 and a Bluetooth technology using anenhanced data rate (EDR) supported by Bluetooth 2.0 or a subsequentversion.

Bluetooth low energy (Bluetooth LE) technology can stably provideinformation of hundreds of kilobytes by consuming less power. Such a BLEtechnology allows devices to exchange information with each other usingan attribute protocol. The BLE method may reduce energy consumption byreducing the overhead of a header and simplifying the operation.

Some of the Bluetooth devices do not have a display or a user interface.The complexity of a connection, management, control, and a disconnectionbetween various Bluetooth devices and Bluetooth devices using similartechnologies is increasing.

Bluetooth supports a high speed at a relatively low cost with relativelylow power consumption. However, Bluetooth is appropriately used within alimited space because it has a maximum transmission distance of 100 m.

However, in the Bluetooth LE technology, the amount of data, which maybe transmitted, has decreased compared to the existing Bluetooth BR/EDR,and thus when a large amount of data is transmitted, it takes long timeand Bluetooth module needs to be continually activated, therebyincreasing power consumption.

DISCLOSURE Technical Problem

An object of the present invention is to provide a method of changingthe data transmission rate in Bluetooth communication.

Another object of the present invention is to provide a method ofimproving the data transmission rate in Bluetooth communication.

Yet another object of the present invention is to provide a method ofnegotiating a packet length in order to improve the date transmissionrate in the Bluetooth initial paring operation.

Yet another object of the present invention is to provide a method ofchanging the data transmission rate during data transmission afterBluetooth connection.

Yet another object of the present invention is to provide a method ofnegotiating a packet length in order to improve the data transmissionrate during data transmission after Bluetooth connection.

Technical Solution

In order to solve the above-described problems, the present inventionprovides a method and apparatus for extending the data length ofBluetooth communication. Specifically, a method of extending the datalength according to an embodiment of the present invention includes:receiving a first message including information of a second device fromthe second device; transmitting a connection request message to thesecond device based on the first message; performing Bluetoothconnection with the second device based on the connection requestmessage; transmitting an extension request message which requestsextension of a transmission data length and a reception data lengththrough the connected Bluetooth; and receiving an extension responsemessage in response to the request message through the connectedBluetooth, wherein the request message includes at least one of firstmaximum transmission data length information, first maximum receptiondata length information, first maximum transmission time information, orfirst maximum reception time information of the first device, andwherein the response message includes at least one of second maximumtransmission data length information, second maximum reception datalength information, second maximum transmission time information, andsecond maximum reception time information of the second device.

Further, the method further includes negotiating the transmission datalength and the reception data length, wherein the transmission datalength may be negotiated based on at least one of third maximumtransmission data length information and third maximum transmission timeinformation, and wherein the reception data length may be negotiatedbased on at least one of third maximum reception data length informationand third maximum reception time information.

Here, third maximum transmission data length information may bedetermined by negotiation as a smaller value among the first maximumtransmission data length information and the second maximum receptiondata length information, the third maximum transmission time informationmay be determined by negotiation as a smaller value among the firstmaximum transmission time information and the second maximum receptiontime information, the third maximum reception data length informationmay be determined by negotiation as a smaller value among the firstmaximum reception data length information and the second maximumtransmission data length information, and the third maximum receptiontime information may be determined by negotiation as a smaller valueamong the maximum reception time information and the second maximumtransmission time information.

Here, the connection request message may include at least one of windowsize information, window offset information, or connect intervalinformation.

Here, the method further includes transmitting a window size updaterequest message for changing a window size; and receiving a responsemessage as a response to the window size update request message.

Further, a method of changing a data length of Bluetooth communicationby a first device in a wireless communication system according to anembodiment of the present invention includes: receiving firstinformation related with whether extension of a transmission data lengthand a reception data length is supported, from a second device;receiving second information related with a data length of the seconddevice from the second device; negotiating the data length based on thesecond information and third information related with a data length ofthe first device; and transmitting the negotiated data length to thesecond device, wherein the second information includes at least one offirst maximum transmission data length information, first maximumreception data length information, first maximum transmission timeinformation, and first maximum reception time information, and whereinthe third information includes at least one of second maximumtransmission data length information, second maximum transmission timeinformation, and second maximum reception time information.

Here, the negotiated data length may include at least one of atransmission data length, a reception data length, transmission time,and reception time.

Here, the transmission data length may indicate a smaller value amongthe second maximum transmission data length information and the firstmaximum reception data length information, the reception data length mayindicate a smaller value among the second maximum reception data lengthinformation and the first maximum transmission data length information,the transmission time may indicate the second maximum transmission timeinformation and the first maximum reception time information, and thereception time may indicate a smaller value among the second maximumreception time information and the first maximum transmission timeinformation.

Here, the first information and the second information may be includedin one message so as to be simultaneously transmitted.

The method further includes transmitting a request message whichrequests the second information.

The method further includes: transmitting a change request message whichrequests a change of the negotiated data length; and receiving a changerequest response message in response to the change request message.

Here, the change request message may include at least one of firstreception data length information and first transmission datainformation, and the change response message may include at least one ofresponse information related with whether the change request is allowed,second reception data length information, and second transmission datalength information.

Here, the second reception data length information may be determinedbased on the first reception data length information, and the secondtransmission data length information may be determined based on thefirst transmission data length information.

An apparatus for extending a data length of Bluetooth communicationincluding a first device in a wireless communication system according toan embodiment of the present invention is provided, wherein the firstdevice may include: a communication unit for transmitting and receivinga signal in a wired way and/or in a wireless way with an external side;and a controller which is functionally connected to the communicationunit, wherein the controller may receive a first message includinginformation of the second device from a second device, transmit aconnection request message to the second device based on the firstmessage, perform Bluetooth connection with the second device based onthe connection request message, transmit an extension request messagewhich requests extension of a transmission data length and a receptiondata length through the connected Bluetooth, and receive an extendedresponse message in response to the request message through theconnected Bluetooth, wherein the request message may include at leastone of first maximum transmission data length information, first maximumreception data length information, first maximum transmission timeinformation, and first maximum reception time information of the firstdevice, and wherein the response message may include at least one ofsecond maximum transmission data length information, second maximumreception data length information, second maximum transmission timeinformation, and second maximum reception time information of the seconddevice.

Here, the controller may negotiate a transmission data length and areception data length, the transmission data length may be negotiatedbased on at least one of third maximum transmission data lengthinformation and third maximum transmission time information, and thereception data length may be negotiated based on at least one of thirdmaximum reception data length and third maximum reception timeinformation.

Here, third maximum transmission data length information may bedetermined by negotiation as a smaller value among the first maximumtransmission data length information and the second maximum receptiondata length information, the third maximum transmission time informationmay be determined by negotiation as a smaller value among the firstmaximum transmission time information and the second maximum receptiontime information, the third maximum reception data length informationmay be determined by negotiation as a smaller value among the firstmaximum reception data length information and the second maximumtransmission data length information, and the third maximum receptiontime information may be determined by negotiation as a smaller valueamong the maximum reception time information and the second maximumtransmission time information.

Here, the connection request message may include at least one of windowsize information, window offset information, or connect intervalinformation.

Here, the controller may transmit a window size update request messagefor changing a window size and receives a response message in responseto the window size update request message.

An apparatus for extending a data length of Bluetooth communicationincluding a first device in a wireless communication system according toan embodiment of the present invention includes: a communication unitfor transmitting and receiving a signal in a wired way and/or in awireless way with an external side; and a controller which isfunctionally connected to the communication unit, wherein the controllerreceives first information related with whether extension of atransmission data length and a reception data length is supported, froma second device, receives second information related with a data lengthof the second device from the second device, negotiates the data lengthbased on the second information and third information related with adata length of the first device, and transmits the negotiated datalength to the second device, wherein the second information includes atleast one of first maximum transmission data length information, firstmaximum reception data length information, first maximum transmissiontime information, and first maximum reception time information, andwherein the third information includes at least one of second maximumtransmission data length information, second maximum transmission timeinformation, and second maximum reception time information.

Advantageous Effects

According to a method of changing the Bluetooth data transmission rateaccording to an embodiment of the present invention, the datatransmission rate may be improved by negotiating a packet length.

Further, according to a method of changing the Bluetooth datatransmission rate according to an embodiment of the present invention,as the date transmission rate is improved through packet lengthnegotiation, the data transmission time may be reduced.

Further, according to a method of changing the Bluetooth datatransmission rate according to an embodiment of the present invention,as the amount of data, which may be transmitted at one time through thepacket length negotiation, increases, the data transmission rate may beimproved, thereby reducing power consumption of Bluetooth device.

Further, according to a method of changing the Bluetooth datatransmission rate according to an embodiment of the present invention,the transmission rate of data, which may be transmitted by a scanningrequest response through a packet length negotiation in the pairingoperation, is improved, thereby increasing the data transmission rate ofBluetooth device.

Further, according to a method of changing the Bluetooth datatransmission rate according to an embodiment of the present invention, alarge amount of data may be transmitted through packet lengthnegotiation after Bluetooth connection, and thereby the datatransmission speed may be improved and the power consumption of theBluetooth device may be reduced.

Further, according to a method of changing the Bluetooth datatransmission rate according to an embodiment of the present invention,the data transmission rate may be changed according to the amount ofdata to be transmitted through packet length negotiation after Bluetoothconnection, and thus efficient data transmission is possible.

DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram showing a protocol stack provided for Bluetoothcommunication to which an embodiment of the present invention may beapplied.

FIG. 2 is a diagram showing an example of an internal block of a deviceto which an embodiment of the present invention may be applied.

FIGS. 3 to 5 are diagrams showing a general connection process ofBluetooth and an example of a packet format.

FIG. 6 is a diagram showing an example of a packet format for improvingthe data transmission rate to which an embodiment of the presentinvention may be applied.

FIGS. 7 to 9 are diagrams showing a process of negotiating a packetlength in the Bluetooth connection process and an example of a packetformat to which an embodiment of the present invention may be applied.

FIGS. 10 and 11 are diagrams showing a process for negotiating a packetlength through a scanning request and a scanning response in theBluetooth connection process and an example of a packet format to whichan embodiment of the present invention may be applied.

FIGS. 12 to 14 are diagrams showing a process for negotiating a packetlength through a scanning request and a scanning response in theBluetooth connection process and an example of a packet format to whichanother embodiment of the present invention may be applied.

FIGS. 15 and 16 are diagrams showing a process for using an extendedscan response through a packet length negotiation in the Bluetoothconnection process and an example of a packet format to which anembodiment of the present invention may be applied.

FIGS. 17 and 18 are diagrams showing a process for changing a packetlength after Bluetooth connection and a packet format to which anembodiment of the present invention may be applied.

FIGS. 19 and 20 are diagram showing a process for extending a packetlength after Bluetooth connection and a packet format thereabout towhich an embodiment of the present invention may be applied.

MODE FOR INVENTION

Hereinafter, in this specification, the contents related to the presentinvention will be described in detail in connection with exemplaryembodiments with reference to the accompanying drawings. It is to benoted that in assigning reference numerals to respective elements in thedrawings, the same reference numerals designate the same elementsthroughout the drawings although the elements are shown in differentdrawings. Furthermore, in describing the embodiments of the presentinvention, a detailed description of the known functions andconstructions will be omitted if it is deemed to make the gist of thepresent invention unnecessarily vague.

Hereinafter, the methods and apparatuses related with the presentinvention will be described in detail with reference to drawings. Theterms “module” and “unit” for components which may be used in thedescription below are used only for the convenience of description andthe terms themselves do not have a distinctive meaning or role.

The electronic devices, which are explained in the presentspecification, may include a mobile phone, a smartphone, a laptopcomputer, a terminal for a digital broadcast, a personal digitalassistant (PDA), a portable multimedia player (PMP), and a navigationsystem. However, it may be easily understood by one of ordinary skill inthe art that the configurations according to the embodiments which aredisclosed in the present specification may also be applied to fixedterminals such as a digital TV and a desktop computer except for thecases which can applied only to mobile terminals.

Signals, which are explained in the present specification, may also betransmitted in the form of frames as well as messages.

FIG. 1 is a diagram showing a protocol stack provided for Bluetoothcommunication to which an embodiment of the present invention may beapplied.

Referring to FIG. 1, (a) shows an example of a protocol stack ofBluetooth basic rate (BR)/enhanced data rate (EDR), and (b) indicates anexample of a protocol stack of Bluetooth low energy (LE).

In detail, as illustrated in (a) of FIG. 4, the Bluetooth BR/EDRprotocol stack may include an upper controller stack 10 and a lower hoststack 20 with respect to a host controller interface (HCI) 18.

The host stack (or host module) 20 refers to hardware for transmittingor receiving a Bluetooth packet to and from a wireless transceivermodule receiving a Bluetooth signal of 2.4 GHz, and is connected to aBluetooth module, the controller stack 10, to control the Bluetoothmodule and performs an operation.

The host stack 20 may include a BR/EDR PHY layer 12, a BR/EDR basebandlayer 14, and a link manager 16.

The BR/EDR PHY layer 12 is a layer transmitting and receiving a 2.4 GHzwireless signal, and in case of using Gaussian frequency shift keying(GFSK) modulation, the BR/EDR PHY layer 12 may transmit data by hopping79 RF channels.

The BR/EDR baseband layer 14 serves to transmit a digital signal,selects a channel sequence hopping 1400 times per second, and transmitsa time slot having a length of 625 us for each channel.

The link manager layer 16 controls a general operation (link setup,control, security) of a Bluetooth connection by utilizing a link managerprotocol (LMP).

The link manager layer 16 may perform the following functions.

-   -   The link manager layer 16 may perform ACL/SCO logical transport,        logical link setup, and control    -   Detach: The link manager layer 16 stops connection and informs a        counterpart device about the reason for stopping connection.    -   The link manager layer 16 performs power control and role        switch.    -   The link manager layer 16 performs security (authentication,        pairing, encryption) function.

The host controller interface layer 18 provides an interface between thehost module and the controller module to allow the host to provide acommand and data to the controller and allow the controller to providean event and data to the host.

The host stack (or host module) 20 includes a logical link control andadaptive protocol (L2CAP) 21, a BR/EDR protocol 22, a general accessprofile (GAP) 23, and a BR/EDR profile 24.

The logical link control and adaptive protocol (L2CAP) 21 may provide atwo-way channels for transmitting data to a specific protocol or aprofile.

The L2CAP 21 may multiplex various protocols and profiles provided froma Bluetooth higher position.

The L2CAP of the Bluetooth BR/EDR uses a dynamic channel, supports aprotocol service multiplexer, retransmission, and a streaming mode, andprovides segmentation and reassembly, per-channel flow control, anderror control.

The BR/EDR protocol 22 and profiles 24 define a service which usesBluetooth BR/EDR and defines an application protocol for exchangingthese data, and the general access profile (GAP) 23 defines a method todiscover and connect a device and provide information to user andprovides privacy.

As illustrated in (b) of FIG. 1, the Bluetooth LE protocol stackincludes a controller stack 30 operable to process a wireless deviceinterface for which timing is important, and a host stack 40 operable toprocess high level data.

First, the controller stack 30 may be implemented by using acommunication module that may include a Bluetooth wireless device, forexample, a processor module that may include a processing device such asa microprocessor.

The host stack may be implemented as part of an OS operated on aprocessor module or may be implemented as instantiation of a package onthe OS.

In some examples, the controller stack and the host stack may beoperated or executed on the same processing device within a processormodule.

The controller stack 30 includes a physical layer (PHY) 32, a link layer(LL) 34, and a host controller interface (HCI) 36.

The physical layer (PHY) (wireless transceiver module 32), a layer fortransmitting and receiving a 2.4 GHz wireless signal, uses a Gaussianfrequency shift keying (GFSK) modulation and a frequency hoppingtechnique including forty RF channels.

The link layer (LL) 34 serving to transmit or receive a Bluetooth packetprovides a function of generating a connection between devices afterperforming an advertising and scanning function using three advertisingchannels, and exchanging data packets of a maximum of 42 bytes throughthirty-seven data channels.

The host stack may include a generic access profile (GAP) 40, a logicallink control and adaptation protocol (L2CAP) 41, a security manager (SM)42, an attribute protocol (ATT) 43, a generic attribute profile (GATT)44, a generic access profile (GAP) 45, and an LE profile 46. However,the host stack 40 is not limited thereto and may include variousprotocols and profiles.

The host stack multiplexes various protocols and profiles provided froma Bluetooth higher position by using the L2CAP.

First, the L2CAP 41 may provide a single two-way channel fortransmitting data to a specific protocol or profile.

The L2CAP 41 may operate to multiplex data between higher layerprotocols, segment and reassemble packages, and manage a multicast datatransmission.

In Bluetooth LE, three fixed channels (one for signaling CH, one forsecurity manager, and one for attribute protocol) are used.

On the other hand, in BR/EDR, a dynamic channel is used, and a protocolservice multiplexer, retransmission, and streaming mode are supported.

The SM 42 is a protocol for certifying a device and providing a keydistribution.

The ATT 43 defines a rule for accessing data of a counterpart device bya server-client structure. The ATT 43 includes six types of messages(request, response, command, notification, indication, and confirmation)as follows.

-   -   {circle around (1)} Request and Response message: A request        message is a message for a client device to request specific        information from a server device, and the response message, as a        response message with respect to the request message, refers to        a message transmitted from the server device to the client        device.    -   {circle around (2)} Command message: It is a message transmitted        from the client device to the server device in order to indicate        a command of a specific operation. The server device does not        transmit a response with respect to the command message to the        client device.    -   {circle around (3)} Notification message: It is a message        transmitted from the server device to the client device in order        to notify an event, or the like. The client device does not        transmit a confirmation message with respect to the notification        message to the server device.    -   {circle around (4)} Indication and confirmation message: It is a        message transmitted from the server device to the client device        in order to notify an event, or the like. Unlike the        notification message, the client device transmits a confirmation        message regarding the indication message to the server device.

The generic access profile (GAP) 45, a layer newly implemented for theBluetooth LE technology, is used to select a role for communicationbetween Bluetooth LED devices and to control how a multi-profileoperation takes place.

Also, the generic access profile (GAP) 45 is mainly used for devicediscovery, connection generation, and security procedure part, defines ascheme for providing information to a user, and defines types ofattributes as follows.

-   -   {circle around (1)} Service: It defines a basic operation of a        device by a combination of behaviors related to data    -   {circle around (2)} Include: It defines a relationship between        services    -   {circle around (3)} Characteristics: It is a data value used in        a server    -   {circle around (4)} Behavior: It is a format that may be read by        a computer defined by a UUID (value type).

The LE profile 46, including profiles dependent upon the GATT, is mainlyapplied to a Bluetooth LE device. The LE profile 46 may include, forexample, Battery, Time, FindMe, Proximity, Time, Object DeliveryService, and the like, and details of the GATT-based profiles are asfollows.

Battery: Battery information exchanging method

Time: Time information exchanging method

FindMe: Provision of alarm service according to distance

Proximity: Battery information exchanging method

Time: Time information exchanging method

The generic attribute profile (GATT) 44 may operate as a protocoldescribing how the attribute protocol (ATT) 43 is used when services areconfigured. For example, the GATT 44 may operate to define how ATTattributes are grouped together with services and operate to describefeatures associated with services.

Thus, the GATT 44 and the ATT 43 may use features in order to describestatus and services of a device and describe how the features arerelated and used.

Internal Block Diagram of Device

FIG. 2 is a diagram showing an example of an internal block of a deviceto which an embodiment of the present invention may be applied.

A server device 200 refers to a device which directly communicates witha client device 100, receives a request, and provides data through aresponse. The service device 200 transmits a notification and indicationmessage to the client device 100 in order to provide data information,and when transmitting the indication message, the confirmation messagemay be received from the client device 100.

One service device may be connected to a plurality of client devices,and may be easily connected with client devices by utilizing bondinginformation.

The client device 100 refers to an apparatus which requests datainformation and transmission to the server device 200. The client device100 refers to a device which receives data transmitted from the serverdevice 200 through the notification and indication message, and when theindication message is received, sends a confirm message.

The client device 100 and the server device 200 may respectively includea communication unit 110 and 210, a user input unit 120 and 220, anoutput unit 130 and 230, a controller 140 and 240, a memory 150 and 250,and a power supply unit 160 and 260.

The communication unit 110 and 210, the user input unit 120 and 220, theoutput unit 130 and 230, the controller 140 and 240, the memory 150 and250, and the power supply unit 160 and 260 are functionally connected inorder to perform the method suggested in the present invention.

The components illustrated in FIG. 2 are not essential, and thus it maybe possible to have more or less components.

The communication unit 110 and 210 may include one or more modules whichallow wireless communication between the device and the wirelesscommunication system or between the device and the network where thedevice is located. For example, the communication unit 110 and 210 mayinclude a broadcast receiving module (not shown), a mobile communicationmodule (not shown), a wireless Internet module (not shown), and a shortdistance communication module (not shown).

The communication unit 110 and 210 may also be called atransmission/reception unit.

The mobile communication module exchanges radio signals with at leastone of a base station, an external terminal or a server over a mobilecommunication network. The radio signal may include a variety of typesof data according to the transmission and reception of voice callsignals, video telephony call signals, or text/multimedia messages.

The wireless Internet module refers to a module for wireless Internetaccess. The wireless Internet module may be internal or external to adevice. A Wireless LAN (WLAN) (Wi-Fi), a Wireless Broadband (WiBro), aWorld Interoperability for Microwave Access (WiMax), and High SpeedDownlink Packet Access (HSPDA) may be used as the wireless Internettechnology.

The short distance communication module refers to a module for shortdistance communication. The short distance communication module mayinclude a Bluetooth module, a radio frequency identification module(RFID) module, an infrared data association module (IrDA) module, ultrawideband (UWB), and ZigBee module.

The server device 200 and the client device 100 may beBluetooth-connected through the Bluetooth module, and data may betransmitted and received through the Bluetooth connection.

Further, the communication units 110 and 210 allow transmission of dataor messages such as command, request, action, and response betweendevices (initiating device-initiated device).

The user input unit 120 and 220 generates input data for operationcontrol of terminal by user. The user input unit 120 and 220 may becomposed of a key pad dome switch, a touch pad (static pressure/staticcurrent), a jog wheel, a jog switch, etc.

The output unit 130 and 230 generates output related to visual,auditory, or tactile senses and may include a display module 132 and 232and a sound output module 134 and 234.

The display module 132 and 232 displays information processed by thedevice. For example, if the device is call mode, the display moduledisplays a User Interface (UI) or Graphic User Interface (GUI) relatedto a call. If the device is video telephony mode or photographing mode,the display module displays a photographed or/and received image, a UI,or a GUI.

The display module 132 and 232 may include at least one of a liquidcrystal display, a thin film transistor liquid crystal display, anorganic light-emitting diode, a flexible display, and a 3D display.

The sound output module 134 and 234 may output audio data received fromthe communication unit 130 and 230 or stored in the memory 150 and 250in incoming call mode, communication mode, recording mode, voicerecognition mode, and broadcast reception mode. The sound output module134 and 234 outputs sound signals related to a function (e.g., areceived call sound and a received message sound) performed in thedevice.

The sound output module 134 and 234 may include a receiver, a speaker,and a buzzer.

The microphone may receive a tone transmitted from the opponent device,and the speaker may transmit tone to the opponent device.

The control unit 140 and 240 refers to a module for controlling anoverall operation of the host device 100 or HID 200 and may performcontrol so that a request to transmit a message or the processing of areceived message is performed through a Bluetooth interface and anothercommunication interface.

The control unit 140 and 240 may be called a controller, amicrocontroller, or a microprocessor and may be implemented by hardware,firmware, software or a combination of them.

The control unit 140 and 240 may include Application-Specific IntegratedCircuits (ASICs), other chipsets, logic circuits and/or data processingdevices.

The memory 150 and 250 may store a program for operation of thecontroller 140 and 240 and may temporally store inputted/outputted data.The memory 150 and 250 may store data about vibration and sounds ofvarious patterns which are outputted at the time of a touch input on thetouch screen.

The memory 150 and 250 is a medium for storing a variety of types ofinformation of the device. The memory 150 and 250 is connected to thecontrol unit 140 and 240 and may store programs, applications, commonfiles, and input/output data for the operations of the control unit 140and 240.

The memory 150 and 250 may include at least of a flash memory type, ahard disk type, a multimedia card micro type, card type memory (e.g., SDor XD memory), Random Access Memory (RAM), Static Random Access Memory(SRAM), Read-Only memory (ROM), Electrically Erasable ProgrammableRead-Only Memory (EEPROM), Programmable Read-Only Memory (PROM),magnetic memory, a magnetic disk and an optical disk. The device mayalso operate in relation to web storage that performs the storagefunction of the memory 240 on the Internet.

The power supply 160 and 260 refers to a module for being supplied withexternal power or internal power and supplying power for the operationsof the elements under the control of the control unit 140 and 240.

Hereinafter, the procedure of a Bluetooth low energy (BLE) technologywill be explained.

FIG. 3 is a diagram showing the flow of a general connection process ofBluetooth to which an embodiment of the present invention may beapplied.

Bluetooth LE procedure may include a device filtering procedure, anadvertising procedure, a scanning procedure, a discovering procedure,and a connecting procedure.

Device Filtering Procedure

The device filtering procedure is a method for reducing the number ofdevices performing a response with respect to a request, indication,notification, and the like, in the controller stack. When requests arereceived from all the devices, it is not necessary to respond thereto,and thus, the controller stack may perform control to reduce the numberof transmitted requests to reduce power consumption.

A first device (device 1) 300 may perform the device filtering processin order to restrict a device which receives an advertisement packet, ascanning request, or a connection request.

Here, the advertising device refers to a device transmitting anadvertisement event, that is, a device performing an advertisement andis also termed an advertiser.

The scanning device refers to a device performing scanning, that is, adevice transmitting a scan request.

In Bluetooth LE, when the scanning device receives some advertisementpackets from an advertisement device, the scanning device needstransmitting a scanning request to the advertisement device. If theadvertisement device, in which the scanning request needs to betransmitted, is filtered in advance, the scanning device may disregardadvertisement packets which are transmitted in the advertisement device.

Even in the connection request process, the device filtering proceduremay be used. If the advance device filtering procedure for a device,which responds to the connection request in a device which requestsconnection, is not used, the device, which receives the connectionrequest, (e.g., an advertisement device which has performed theadvertisement) needs to respond to the connection request.

The device, which requests a connection, may be expressed as aninitiating device or an initiator.

The scanning device may use a device filtering procedure in order torestrict devices to transmit the scanning request or connection requestto the advertisement device.

Advertising Procedure

The first device 300, which is an advertisement device, performs anadvertisement procedure in order to perform non-directional broadcaststo the devices within the area (S310). Here, non-directional broadcastsrefer to broadcasts in all directions, not a broadcast in a certaindirection. On the other hand, a directional broadcast refers to abroadcast in a certain direction. The non-directional broadcast isgenerated output a connection procedure between the advertisement deviceand a device in the listening state (hereinafter, referred to as“listening device”).

The advertisement procedure is used to establish Bluetooth connectionwith a neighboring initiating device. Further, the advertisementprocedure may be used to provide periodic broadcasts of user data toscanning devices which are performing listening in the advertisementchannel. In the advertisement procedure, all advertisements (oradvertisement event) are broadcast through an advertisement physicalchannel.

A Bluetooth LE device, which is connected to Bluetooth LE Piconet, maybe advertised by using a specific type of the advertisement event.

A second device (device 2) 400, which is a scanning device, may transmita scanning request in order to obtain additional user data from theadvertisement device (S320). The first device 300 transmits a responseto the scanning request to the second device 400 which has transmittedthe scanning request, through the same advertisement physical channel asthe advertisement physical channel which has received the scanningrequest (S330).

The broadcast user data, which is sent as part of advertisement packets,is dynamic data, but scanning response data is generally static data.

The advertisement device may receive a connection request from theinitiating device on the advertisement (broadcast) physical channel. Ifthe advertisement device has used a connectable advertisement event andthe initiating device has not been filtered by the device filteringprocedure, the advertisement device stops advertisement and enters aconnected mode. The advertisement device may restart advertisement afterthe connection mode.

Scanning Procedure

The second device 400, which performs scanning, performs the scanningprocedure in order to listen to a non-directional broadcast of user datafrom advertisement devices which use the advertisement physical channel.

The second device 400 transmits the scanning request to theadvertisement device through the advertisement physical channel in orderto request additional user data from the advertisement device (S320).The first device 300, which is the advertisement device, transmits ascanning request to the scanning request including additional user datawhich has requested in the scanning device through the advertisementphysical channel.

The scanning procedure may be used while connected with anotherBluetooth LE device in Bluetooth LE Piconet.

If the scanning device receives a broadcasted advertisement event and isin the initiator mode which may initiate the connection request, thesecond device 400 may start Bluetooth connection with the advertisementdevice by transmitting a connection request to the first device 300through the advertisement physical channel (S340).

If the device transmits a connection request to the advertisement devicein the second device 400, the scanning device stops initiator modescanning for an additional broadcast and enters a connection mode.

Discovering Procedure

Devices which allow Bluetooth communication (hereinafter, referred to as“Bluetooth device”) perform the advertisement procedure and scanningprocedure in order to discover neighboring devices or to be discoveredby other devices within a given area.

The discovering procedure is asymmetrically performed. The Bluetoothdevice, which tries to find other neighboring devices, is called adiscovering device, and listens in order to find devices which advertisean advertisement event which allows scanning. The Bluetooth device,which is discovered by another device and is thereby available, iscalled a discoverable device, and positively broadcasts an advertisementevent so that another device may perform scanning through theadvertisement (broadcast) physical channel.

Both the discovering device and the discoverable device may already havebeen connected to other Bluetooth devices in Piconet.

Connecting Procedure

The connection procedure is asymmetric, and while a certain Bluetoothdevice performs an advertisement procedure, the connection procedurerequires performance of the scanning procedure by another Bluetoothdevice.

That is, the advertisement procedure may be the purpose, and as aresult, only one device will respond to the advertisement. Afterreceiving a connectable advertisement event from the advertisementdevice, the connection may be initiated by transmitting a connectionrequest to the advertisement device through the advertisement(broadcast) physical channel.

Hereinafter, the operation states in BLE technology, i.e., theadvertising state, the scanning state, the initiating state, and theconnection state, will be briefly described.

Advertising State

A link layer (LL) enters an advertising state according to aninstruction from a host (stack). In a case in which the LL is in theadvertising state, the LL transmits an advertising packet data unit(PDU) in advertising events.

Each of the advertising events include at least one advertising PDU, andthe advertising PDU is transmitted through an advertising channel indexin use. After the advertising PDU is transmitted through an advertisingchannel index in use, the advertising event may be terminated, or in acase in which the advertising device may need to secure a space forperforming other function, the advertising event may be terminatedearlier.

Scanning State

The Link Layer enters the scanning state according to an instructionfrom the host (stack). In the scanning state, the LL listens toadvertising channel indices.

The scanning state includes two types: passive scanning and activescanning. Each of the scanning types is determined by the host.

Time for performing scanning or an advertising channel index are notdefined.

During the scanning state, the Link Layer listens to an advertisingchannel index in a scan window duration. A scan interval is defined asan interval between start points of two continuous scan windows.

When there is no collision in scheduling, the Link Layer should listenin order to complete all the scan intervals of the scan window asinstructed by the host. In each scan window, the Link Layer should scanother advertising channel index. The Link Layer uses every availableadvertising channel index.

In the passive scanning, the Link Layer only receives packets and cannottransmit any packet.

In the active scanning, the Link Layer performs listening in order to berelied on an advertising PDU type for requesting advertising PDUs andadvertising device-related additional information from the advertisingdevice.

Initiating State

The Link Layer enters the initiating state according to an instructionfrom the host (stack). When the Link Layer is in the initiating state,the Link Layer performs listening on advertising channel indices.

During the initiating state, the Link Layer listens to an advertisingchannel index during the scan window interval.

Connection State

When the device performing a connection state, that is, when theinitiating device transmits a CONNECT_REQ PDU to the advertising deviceor when the advertising device receives a CONNECT_REQ PDU from theinitiating device, the LL enters a connection state.

It is considered that a connection is generated after the Link Layerenters the connection state. However, it is not necessary to considerthat the connection should be established at a point in time at whichthe Link Layer enters the connection state. The only difference betweena newly generated connection and an already established connection is aLink Layer connection supervision timeout value.

When two devices are connected, the two devices play different roles.

An Link Layer serving as a master is termed a master, and an Link Layerserving as a slave is termed a slave. The master adjusts a timing of aconnecting event, and the connecting event refers to a point in time atwhich the master and the slave are synchronized.

Such a Bluetooth LE procedure adopts only three channels less than theprocedure of Bluetooth BR/EDR so as to be used as the advertisementchannels, and thus the power of 10 to 20 times less than that ofBluetooth BR/EDR technology is used.

However, the amount of data, which may be transmittable, is reduced thanBluetooth BR/EDR, and thus longer time is needed when transmitting alarge amount of data and the power consumption may be increased.Hereinafter, in order to consider the length of data which may betransmitted Bluetooth LE technology, the packet structure of BluetoothLE will be explained.

FIGS. 4 and 5 are diagrams showing an example of a Bluetooth packetformat.

Referring to FIGS. 4 and 5, the Bluetooth LE includes one (a) link layerpacket 410 which is used for both the advertisement channel packet andthe data channel packet.

Each packet is composed of four fields of a preamble, an access address,a packet data unit (PUD), and CRC.

The length of the PDU is the minimum 2 octets to the maximum 39 octets,and the length of data, which may be transmitted at one time throughBluetooth LE, may be determined according to the length of the PDU.

When one packet is transmitted in the advertisement physical channel,the PDU may be the advertisement channel PDU, and when one packet istransmitted in the data physical channel, the PDU may become the datachannel PDU.

PDU (Advertising Channel PDU)

(b) An advertising channel PDU 420 has a 16 bit header 430 and a payloadof minimum 0 octet to maximum 31 octets, and (c) the header 430 of theadvertising channel PDU may be composed of a PDU type, reserved forfuture used (RFU), TxAdd, RxAdd, and Length fields.

The TxAdd field and the RxAdd field include information for the PDUtype, and the length field indicates the length of the payload field andmay be expressed as octet.

When the TxAdd field or the RxAdd field are not defined, this may beused as the RFU field.

The PDU type file indicates the PDU type as defined in Table 1 below.

TABLE 1 PDU Type Packet Name 0000 ADV-IND 0001 ADV_DIRECT_IND 0010ADV_NONCONN_IND 0011 SCAN_REQ 0100 SCAN_RSP 0101 CONNECT_REQ 0110ADV_SCAN_IND 0111-1111 Reserved

The maximum length of the advertising channel PDU is 39 octets, and thusthe length of data, which may be transmitted through the advertisementat one time, is 31 octets. Hence, there is a limit in the informationwhich may be provided.

Advertising PDU

The following advertising channel PDU types are called an advertisingPDU and are used in the specific event.

ADV_IND: Connectable non-directional advertising event

ADV_DIRECT_IND: Connectable directional advertising event

ADV_NONCONN_IND: Non-connectable non-directional advertising event

ADV_SCAN_IND: Scanning-possible non-directional advertising event

The PDUs are transmitted in the link layer in the advertising state andare received by the link layer in the scanning state or initiatingstate.

Scanning PDUs

The following advertising channel PDU type is called a scanning PDU andis used in the state which is explained below.

SCAN_REQ: This is transmitted by the link layer in the scanning stateand is received by the link layer in the advertising state.

SCAN_RSP: This is transmitted by the link layer in the advertising stateand is received the link layer in the scanning state.

Initiating PDUs

The following advertising channel PDU type is called an initiating PDU.

CONNECT_REQ: This is transmitted by the link layer in the initiatingstate and is received by the link layer in the advertising state.

Data Channel PDU

The (a) data channel PDU 510 of FIG. 5 has a 16 bit header and payloadsof various lengths and may include a message integrity check (MIC).

The data channel PDU header 520 may be composed of a logical linkidentifier (LLID), a next expected sequence number (NESN), a sequencenumber (SN), more data (MD), and a length field.

The LLID field includes information for identifying whether the datachannel PDU is LL data PDU or LL control PDU.

The NESN field and the SN field are fields which perform acknowledge(ACK) function when transmitting and receiving data. When transmittingdata, the SN field value is compared with the NESN field value. Then ifthe values are the same, it is considered as NAK (negative acknowledge),and previous data is sent again. If the values are not the same, the SNfield value (SN field is 1 bit information, and thus 0 or 1) isincreased and new data may be transmitted.

When receiving data, the SN field value is compared with the NESN fieldvalue are compared. If the values are the same, the NESN field value isincreased and new data is received, and if different, it is consideredas NAK and received data is disregarded.

At this time, if received data is broken, the NESN field value is notchanged, and thus when transmitting the next packet, the SN field valueand the NESN field value become the same and thus data is retransmitted.

The MD field may be used to indicate that there are other data to betransmitted by the device.

In the data channel PDU, the PDU length of the link layer packet 410 isdetermined as the maximum 39 octets, and thus the length of data, whichcan be transmitted at one time, is limited to 37 octets.

As considered with reference to FIGS. 4 and 5, the purpose of theBluetooth LE technology is to quickly transmit a small amount of data byusing low power, and thus the length of data, which may be transmittedat one time through the advertising channel PDU, is limited and therebytransmission of a large amount of data takes longer time and powerconsumption may increase.

Hereinafter, the data format setting method and data format for solvingthis problem will be considered.

FIG. 6 is a diagram showing an example of a packet format for improvingthe data transmission rate to which an embodiment of the presentinvention is applied.

Referring to FIG. 6, the length of data, which may be transmitted at onetime, by setting the length of the PDU of the link layer packet to begreater than that of the PDU of the existing link layer packet.

Specifically, in Bluetooth LE technology, the length of the PDUincluding data to be transmitted in (a) link layer packet 610 which isused in the advertising channel packet and the data channel packet maybe extended to the maximum 249 octets.

As the PDU length of the link layer packet 610 is extended, the lengthsof the advertising channel PDU and the data channel PDU which use thelink layer packet 610 format may be extended to the maximum 249 octets,and the payload may also be extended to the maximum 245 octets.

Further, in order to use such an extended link layer packet, whether theextended link layer packet is supported needs to be informed of otherdevices. Hence, the long length field is added to the header 620 of theadvertising channel PDU and the header 630 of the data channel PDU, andthereby it may be notified whether the extended link layer packet issupported to other devices.

Further, as the length of the link layer PDU is extended, the payloadlength of the link layer PDU is also extended, and thus the length ofthe length field, which indicates the length of the payload in theadvertising PDU header 620 and the data channel PDU header 630, is alsochanged to 8 bits so that the length of the extended payload may beindicated. The packet format of FIG. 6 may be used in the followingembodiment.

When such an extended packet format is used, the length of thetransmittable data becomes greater, compared with the existing packetformat, and when transmitting a large amount of data, the number oftimes which exchange data between devices is reduced, thereby the datatransmission time is reduced, and thereby the power consumption of thedevice may also be reduced.

FIGS. 7 to 9 are diagrams showing a process for negotiating a packetlength in the Bluetooth connection process and an example of a packetformat.

Referring to FIGS. 7 to 9, the data length may be negotiated through theadvertisement and connection request.

Specifically, if the first device 300 tries to connect to the devicethrough Bluetooth LE technology, the first device 300 may transmit anadvertisement message or frame to the second device 400 (S710).

The advertisement message or frame has the same format as that of thelink layer 610 of FIG. 6, and if the first device 300 supports theextended link layer PDU, this can be notified to the second device 400through the advertisement channel PDU header 620 of FIG. 6.

The PDU payload of the advertisement message or frame may have theformat of (a) or (b) of FIG. 8. For example, the PDU payload of theADV_IND, the ADV_NONCONN_IND, and the ADV_SCAN_IDN has the same packetformat as that of (a) of FIG. 8, and the ADV_DIRECT_IND has the samepacket as that of (b) of FIG. 8.

The advertisement channel PDU payload of (a) and (b) of FIG. 8 commonlyincludes AdvA field including the address of the first device 300 whichis the advertising device, and AdvData field including the supporteddata length.

The (b) advertising PDU payload 820, which is used in theADV_DIRECT_INT, may further include InitA field which indicates theaddress of the device which requests connection.

AdvData field 830 of (c) advertisement channel PDU may include AdvDatatype which indicates the type of the advertising message or frame,maximum RX LE payload size field which indicates the receivable maximumdata length, and maximum TX LE payload size field which indicates thetransmittable maximum data length.

The second device, which receives the advertising message or frame, mayunderstand whether the first device 300 supports the extended LE packetthrough the length field which is included in the header of the frame orthe advertising message, and a connection request may be transmitted tothe first device 300 based on information which is included in thereceived advertising message or frame (S720).

At this time, the data channel PDU payload 910 of the connection requestmay include InitA field, AdvA field, and LL data field.

The InitA ma include the address of the device which performs aconnection request, for example, the address of the second device 400 ofFIG. 7.

The LL data field may include the field of Table 2, Tx payload size, Rxpayload size, maximum RX LE payload size, and maximum TX LE payload sizefield of FIG. 9.

TABLE 2 AA CRClint WinSize WinOffset Interval Latency Timeout ChM HopSCA (4 octets) (3 bits) (3 bits) (3 bits) (3 bits) (3 bits) (3 bits) (3bits) (3 bits) (3 bits)

The AA field includes an access address for link layer connection.

The CRCInt field includes an initial setting value for cyclicalredundancy check (CRC) calculation which notifies of whether the contentof the frame has been changed during transmission.

The WinSize field includes the value for the length of the section wherethe actual data can be transmitted within a single connect Interval, andthe WinOffset field may include an offset value until the actualtransmit window is started within the connect interval.

The interval field may include an interval between connect events.

The latency field is used to cancel connection when there is no dataexchange during a specific event while connection is maintained.

The timeout field includes time includes time which is judged asconnection-impossible when the device cannot further connect.

The chM field includes information of the channel which is used and thechannel which is not used at the channel hopping, and the hop fieldincludes the distance value to the following channel when the channelhopping is performed in Bluetooth LE.

The SCA field may include sleep clock accuracy information of the masterdevice, and the accuracy level is shown in Table 3 below.

TABLE 3 SCA masterSCA 0 251 ppm to 500 ppm 1 151 ppm to 250 ppm 2 101ppm to 150 ppm 3  76 ppm to 100 ppm 4 51 ppm to 75 ppm 5 31 ppm to 50ppm 6 21 ppm to 30 ppm 7  0 ppm to 20 ppm

Maximum RX LE payload size field of FIG. 9 includes the maximum datalength which may be received by the second device 400, and the maximumTX LE payload size field may include the maximum data length which maybe transmitted by the first device 300.

The Tx payload size and the Rx payload size field include data lengthinformation which is to be used in the transmission and reception ofdata which is determined by the negotiation of the second device 400.

That is, the minimum value among the maximum receiving data length,which is received from the first device 300 and the maximum data lengthof the second device 400 may be determined as the Tx payload size, andthe minimum value among the maximum transmission data length which isreceived from the first device 300 and the maximum receiving data lengthwhich may be self-provided may be determined as the Rx payload size.

The Formula 1 below is an equation for determining the Tx payload size,and the Formula 2 below is an equation for determining the Rx payloadsize.

RX Payload Siz=Min(Peer Maximum TX LE Payload Size, Maxumum RX PayloadSize)  [Equation 1]

TX Payload Size=Min(Peer Maximum RX LE Payload Size, Maximum TX PayloadSize)  [Equation 2]

For example, when the maximum transmission payload value, which may besupported by the first device 300, is 150, and the maximum receivingpayload value is 150, and the maximum transmission payload value, whichmay be supported by the second device 400, is 230, and the maximumreceiving payload value is 230, if the first device 300 transmits theadvertising message or frame, in which AdvData Type is 0xF3FB, themaximum RX LE payload size value is 150, and the maximum TX LE payloadsize value is 150, to the second device 400, the second device 400 mayunderstand that the maximum of the receiving payload length and thetransmitting payload length of the first device 300 is 150.

The LL data field may include the field of Table 2, the Tx payload sizefield, and the Rx payload size field.

Thereafter, when the maximum receiving payload value, which may besupported by the second device 400, is 230, and the maximum transmissionpayload value is 230, the second device 400 may determine the RX payloadsize as 150 and the TX payload size value as 150 so as to transmit aconnection request to the first device 300.

The first device 300 and the second device 400 may extend the payloadlength through such a method and may transmit and receive data throughthe extended payload.

As another embodiment of the present invention, the first device 300informs the second device 400 of the extended LE packet through theadvertising message or advertising frame, but the first device 300 maynot inform of the value of the maximum RX LE payload size and the valueof the maximum TX LE payload size.

In this case, the second device 400 tries connection to the first device300 with a general data length which is not the extended LE packet andmay inform the first device 300 of the value of the maximum RX LEpayload size and the value of the maximum TX LE payload size through aconnection request.

In the present embodiment, connection is not made with the extended datalength, but later, for the case where the data length is extended,information of the second device 400 is transmitted to the device 300.

FIGS. 10 and 11 are diagrams showing a process for negotiating a packetlength through a scanning request and scanning response in the Bluetoothconnection process and an example of a packet format.

Referring to FIGS. 10 and 11, the Bluetooth LE data length may beextended by providing the data length extension request and informationthrough the scanning request which requests additional deviceinformation during Bluetooth LE connection.

Specifically, when the first device 300 tries connection to the seconddevice 400 through Bluetooth LE technology, the first device 300 maytransmit an advertisement message or frame to the second device 400(S1010).

The advertisement message or frame may have the same format as that ofthe link layer format 610 of FIG. 6.

When the first device 300 supports an extended link layer PDU, the firstdevice 300 ay inform the second device 400 of the fact that the extendedlink layer PDU is supported, through the length field of theadvertisement channel PDU header.

The advertisement channel PDU payload 1110 of the advertisement messageor frame may include AdvA field and Adv data field.

The AdvA field may include the address of the first device 300 which isan advertisement device and may include information of the first device300. However, in the present embodiment, unlike FIGS. 7 to 9, theAdvData field does not include extended packet length information whichis supported by the first device 300.

Hence, the second device 400 may transmit a scanning request to thefirst device 300 in order to obtain extended packet length informationwhich is supported by the first device 300 (S1020).

The packet format of the scanning request is the same as that of thelink layer packet 610 of FIG. 6, and the header may also have the samepacket structure as that of the advertisement channel PDU header 620 ofFIG. 6.

At this time, in the scanning request header, the long length field isused to request supported data length information to the first device300.

The (b) scanning request PDU payload 1120 of the scanning request mayinclude ScanA field and AdvA field, and the ScanA includes the addressof the second device 400 which is a device which requests information,and the AdvA field includes the address of the first device 300.

The first device 300, which has received the scanning request, mayinclude self-supported packet length information in the scanningresponse and transmit the information to the second device 400 (S1030).

The scanning response may include (c) scanning response PDU payload1130, and the scanning response PDU payload 1130 may include Adv fieldincluding address of the first device 300 which is a device thatprovides scanning information, and ScanRspData field includingadditional information.

The Scan RspData field may include ScanRspData type field, maximum RX LEpayload size field, and maximum TX LE payload size field which indicatethe message type.

The second device 400, which receives transmission of the scanningresponse, negotiates the length of the data packet in the same method asthe method explained in FIGS. 7 to 9, then in order to perform Bluetoothconnection with a negotiated new data length, a connection request maybe transmitted to the first device 300 (S1040).

For example, when the maximum transmission and reception data length,which may be supported by the first device 300, is 150, and the maximumtransmission and reception data length, which may be supported by thesecond device 400, is 230, the second device 400 may set RX/TX payloadsize as 150 by negotiation.

The data channel PDU payload format of the connection request is thesame as that of FIG. 9, and the format of the LL data may include thefield of Table 1, Tx payload size field, Rx payload size field, maximumRX LE payload size field, and maximum TX LE payload field of FIG. 9.

FIGS. 10 and 11 are diagrams showing an embodiment of performing aconnection request with the extended data length format by obtaining thesupportable maximum transmission and reception data length informationthrough a scanning request and a scanning response when the first device300 notifies the second device 400 of only whether the extended datapacket is supported.

Through the present embodiment, when connection is made by usingBluetooth LE technology, a packet having a data length which is moreextended than the existing data packet length may be used, and therebywhen transmitting a large amount of data, the number of times of packettransmission and the data transmission time are reduced, and the powerconsumption of the device is reduced.

FIGS. 12 to 14 are diagrams showing a process for negotiating a packetlength through a scanning request and a scanning response in theBluetooth connection process and another example of a packet format towhich the present invention is applied.

Referring to FIGS. 12 to 14, the first device 300 may inform neighboringdevices of whether the extended data packet is supported, throughadvertisement, and thereby the second device 400 may beBluetooth-connected to the first device 300 with the extended datapacket format.

Specifically, when the first device 300 tries connection to the seconddevice 400 through Bluetooth LE technology, the first device 300 maytransmit an advertisement message or frame to the second device 400(S1210).

The advertisement message or frame has the same format as that of thelink layer packet 610 of FIG. 6, and when the first device 300 supportsthe extended link layer PDU, the fact that the extended link layer PDUis supported may be notified to the second device 400 through the lengthfield of the advertisement channel PDU header of FIG. 6.

The advertisement message or frame includes an advertisement channel PDUpayload 310, and the advertisement channel PDU payload 1410 may includeAdvaA field and AdvData field.

However, in the present embodiment, unlike FIGS. 7 to 9, the AdvDatafield does not include extended packet length information which issupported by the first device 300.

Hence, the second device 400 may request a scanning request to the firstdevice 300 in order to obtain additional information of the first device300 (S1220).

The packet format of the scanning request is the same as that of thelink layer packet 610 of FIG. 6, and the header may also have the samepacket structure as that of the advertisement channel PDU header 620.

At this time, in the header of the scanning request, the long lengthfield is used to request supported data length information to the firstdevice 300.

The scanning request includes scanning request PDU payload 1320, and thescanning request PDU payload 1320 may include ScanA field, AdvA field,and ScanReqData field.

The ScanReqData field includes extended packet length information whichis supported by the second device 400.

The ScanReqData field may include ScanReqData type field, maximum RX LEpayload size field, and maximum TX LE payload size field which indicatethe type of the ScanReqData.

The maximum RX LE payload size field includes maximum receiving datalength information which may be supported by the second device 400, andthe maximum TX LE payload size field includes maximum transmission datalength information which may be supported by the second device 400.

The first device 300, which has received the scanning request, mayinclude the self-supported packet length information in the scanningresponse and transmit the information to the second device 400 (S1230).

The scanning response may include a (c) scanning response PDU payload1330, and the (c) scanning response PDU payload 1330 may include theaddress of the first device 30, which is a device that provides scanninginformation, and ScanRspData field including the scanning information.

The Scan RspData field may include ScanRspData type, the maximum RX LEpayload size field, and the maximum TX LE payload size field, whichindicate the message type.

The second device 400, which receives the transmitted scanning response,negotiates the length of the data packet in the same method as themethod explained in FIGS. 7 to 9, then may transmit a connection requestto the first device 300 with a negotiated new data length (S1240).

The connection request may include the data channel PDU payload 1410,and the data channel PDU payload may include InitA field, AdvA field,and LL data field.

The LL data field may include the field of the above Table 2, Tx payloadsize field, and Rx payload size field.

The Tx payload size field may include new negotiated transmission datalength information, and the Rx payload size field may include newnegotiated receiving data length information.

For example, the second device 400, which comes to understand that thefirst device 300 supports the extended packet through advertisement, maytransmit a scanning request including information that the supportablemaximum transmission and reception data length is 150 octets, to thefirst device 300.

The first device 300 may transmit a scanning response includinginformation that the supportable maximum transmission and reception datalength is 170 octets, to the second device 400 in response to thescanning request.

Thereafter, the second device 400 may determine 150 octets, which is theminimum value among the maximum transmission and reception data lengthof the first device 300 and the maximum transmission and reception datalength of the second device 400 itself, as the extended data length, anda connection request including the determined value may be transmittedto the first device 300.

The embodiments of FIGS. 12 to 14 are different from the embodiments ofFIGS. 10 and 11 in that the second device 400 transmits supportedmaximum data length information along with the scanning request when thesecond device 400 transmits a scanning request to the first device 300.

FIGS. 15 and 16 are diagrams showing a process for using a scanningresponse which is extended through packet length negotiation in theBluetooth connection process and an example of a packet format to whichthe present invention is applied.

Referring to FIGS. 15 and 16, a scanning response message may betransmitted by using an extended data packet according to whether theextended data packet is supported in the Bluetooth connection process.

Specifically, if the first device 300 tries connection to the seconddevice 400 through Bluetooth, the first device 300 may transmit anadvertisement message or frame to the second device 400 (S1510).

The advertisement message or frame has the same format as the link layerpacket 610, and when the first device 300 supports the extended linklayer PDU, the fact that the extended link may PDU is supported may benotified to the second device 400 through the length field of theadvertisement channel PDU header 620 of FIG. 6.

At this time, the PDU type field of the advertisement channel PDU headermay have the value of “0110”, which is the value of ADV_SCAN_IND thatindicates a scanning-possible non-directional advertisement event inTable 1.

The advertisement message or frame may include (a) advertisement channelPDU payload 1610, and the advertisement PDU payload 1610 may includeAdvA field and Adv data field.

The AdvData field may include AdvData type which indicates the type ofthe advertisement message or frame, the maximum RX LE payload size fieldwhich indicates the receivable maximum data length, and the maximum TXLE payload size field which indicates the transmittable maximum datalength.

The second device 400 receives an advertisement message or frame whichallows a scanning request and has been transmitted from the first device300, and thus the second device 400 may transmit a scanning requestwhich requests additional information of the first device 300 (S1520).

The scanning request may include (b) scanning request PDU payload 1620,and the scanning request PDU payload 1620 may include ScanA field, AdvAfield, or ScanReqData field.

The ScanReqData field is a field including information includinginformation on the maximum data length which may be supported by thesecond device 400 itself, and may include ScanReqData type field,maximum RX LE payload size field, and maximum TX LE payload size field.

The ScanReqData type field includes information on the data type of thescanning request, and the maximum RX LE payload size field includesinformation on the length of the maximum receiving data packet which maybe supported by the second device 400.

The maximum TX LE payload size field includes information on the maximumreceiving data packet which may be supported by the second device 400.

The first device 300, which has received a scanning request, maynegotiate the extended receiving data length and the extendedtransmission data length based on information on the maximum data packetlength which may be supported by the second device 400 and the maximumdata packet length which may be supported by the first device 300.

That is, the first device 300 may determine the extended receiving datalength or extended transmission data length as the minimum value amongthe maximum transmission and reception data lengths which may besupported by the first device 300 and the second device 400 by using theabove formula 1 and formula 2.

For example, when the length of the maximum transmission and receptiondata packet, which may be supported by the first device 300, is 150octets, and the length of the maximum transmission and reception datapacket, which may be supported by the second device 400, is 130 octets,the first device 300 may determine the extended transmission andreception data length as 130 octets.

Thereafter, the first device 300 may transmit a scanning response to thesecond device 400 by using the data format to which the extended datapacket length has been applied (S1530).

The scanning response may include (c) scanning response PDU payload1630, and the scanning response PDU payload 1630 may include AdvA fieldand ScanRspData field.

The ScanRspData field may have the same length (e.g., 130 octets) asthat of the value of the extended transmission data length which hasbeen negotiated by the first device 300.

FIGS. 17 and 18 are diagrams showing a process for changing the packetlength after Bluetooth connection and a packet format to which thepresent invention is applied.

Referring to FIGS. 17 and 18, after the transmission and reception datalength is negotiated in the Bluetooth connection procedure, thenegotiated transmission and reception data length may be changed duringthe data transmission and reception.

Specifically, the first device 300 may transmit an advertisement messageor frame for Bluetooth connection (S1710). At this time, theadvertisement message or frame has the same packet format as that formatwhich has been explained in FIGS. 6 and 8.

The second device 400, which has received the advertisement message orframe, is not illustrated in FIG. 17, but when necessary (e.g., whenadditional information is needed), a scanning request may be transmittedto the first device 300, and the second device 400, which has receivedthe scanning request, may transmit the scanning response to the firstdevice 300.

Thereafter, the second device 400 performs Bluetooth connection bytransmitting a connection request including information for Bluetoothconnection (S1720).

In the process of Bluetooth connection the first device 300 and thesecond device 400 may negotiate the extended transmission and receptiondata packet length through one of methods which have been explained withreference to FIGS. 7 to 16.

Thereafter, the first device 300 transmits the maximum data lengthchange request 1810 to the second device 400 when the length of thetransmission and reception data packet needs to be changed while thesecond device 400 transmits and receives data by using a data packet towhich the negotiated length of the transmission and reception datapacket is has been applied (S1730).

The maximum data length change request 1810 may include Op code fieldand CtrData field. The Op code field indicates types of link layer (LL)control packets which transmit Bluetooth control command and may havethe value of Table 4.

TABLE 4 Opcode Control PDU Name 0x00 LL_CONNECTION_UPDATE_REQ 0x01LL_CHANNEL_MAP_REQ 0x02 LL_TERMINATE_IND 0x03 LL_ENC_REQ 0x04 LL_ENC_RSP0x05 LL_START_ENC_REQ 0x06 LL_START_ENC_RSP 0x07 LL_UNKNOWN_RSP 0x08LL_FEATURE_REQ 0x09 LL_FEATURE_RSP 0x0A LL_PAUSE_ENC_REQ 0x0BLL_PAUSE_ENC_RSP 0x0C LL_VERSlON_IND 0x0D LL_REJECT_IND 0x0ELL_SLAVE_FEATURE_REQ 0x0F LL_CONNECTION_PARAM_REQ 0x10LL_CONNECTION_PARAM_RSP 0x11 LL_REJECT_IND_EXT 0x12 LL_PING_REQ 0x13LL_PING_RSP 0x14 LL_LENGTH_REQ 0x15 LL_LENGTH_RSP 0x16 LL_Window_REQ0x17-0xFF Reserved for Future Use

In this case, the Op code field is the transmission of the controlpacket for changing the maximum transmission and reception data lengthand thus the Op code field may have “0x14” value of the above Table 4.

The CtrData field may include RX LE payload size field includinginformation on the length of the received data to be changed and TX LEpayload size including information on the length of the transmitted datato be changed.

The second device 400, which has received the maximum data length changerequest, may transmit the maximum data length change response 1820 tothe first device 300 in response thereto so as to change the maximumdata length (S1740).

The maximum data length change response 1820 may include Op code fieldand Ctr data field.

The Op code is the Op code of the response to the maximum data lengthchange request and thus the Op code may include “0x15” value of theabove Table 2.

The Ctr Data field may include Rsp code field, RX LE payload size field,and TX LE payload size field.

The Rsp code field may include information related with whether thesecond device 400 is allowed with respect to the maximum data lengthchange of the first device 300 and may include OK (allow change), NEW(provide new value), and Reject (acceptance impossible).

The RX LE payload size field and the TX LE payload size field includelength information of the transmission and reception data packet whichhas been changed based on the change request of the first device 300.

As an example of the transmission and reception data packet lengthchange, if the first device 300 tries to change the data length to 150octets, the first device 300 may transmit the maximum data length changerequest to the second device 400 by setting the values of the RX LEpayload size field and the TX LE payload size field respectively to 150octets.

When the second device 400, which has received the maximum data lengthchange request, decides to change the length of the transmission andreception data packet to 150 octets or a value less than 150 octets(e.g., 120 octets), the Rsp code may be set as OK value which allows thechange.

However, when the second device 400 decides not to change the datalength, the Rsp code may be set as Reject value which indicatesacceptance-impossible.

When Rsp type field is set as Reject value, the maximum data lengthchange will not be allowed, and thus CtrData of the maximum data lengthchange response 1820 may not include values of the RX LE payload sizefield and the TX LE payload size field.

If the second device 400 tries to change the transmission and receptiondata length with 180 octets which is a value greater than the valuewhich is intended to be changed by the first device 300, a newtransmission and reception data length value and the Rsp code value areset as New so that the maximum data response may be transmitted to thefirst device 300.

The first device 300, which receives the maximum data length changeresponse where Rsp code has been set as New, from the second device 400,the first device 300 may determine whether a newly suggested data lengthvalue is allowed.

That is, the first device 300 may determine OK (change-allowed), NEW(new value provided), or Rejection (acceptance-impossible) again for thedata length value which has been re-suggested by the second device 400.

Thereafter, the first device 300 may change the maximum transmission andreception data length by transmitting the maximum data length changeresponse to the second device 400.

At this time, in the case where 180, which is the maximum data lengthvalue that is provided by the second device 400, is possible only whentransmitting data, the first device 300 may set Rsp code value to OK, RXLE payload size field value to 150, and the TX LE payload size fieldvalue to 180 so as to transmit the maximum data change response to thesecond device 400.

Through the above-explained data packet length change process, the datapacket length, which has been negotiated at the Bluetooth connectionoperation or after Bluetooth connection, may be extended or reduced.

That is, when the first device 400 and the second device 400 determinethe data packet length as a value less than 150 octets by negotiation inthe connection operation, the data packet length change procedure hasperformed the data length change procedure in order to extend the datalength after the Bluetooth connection.

However, when the first device 300 and the second device 400 determinethe data length as 180 octets or greater by negotiation in theconnection operation, the data packet length change procedure hasperformed the data length change procedure in order to reduce the datalength after Bluetooth connection.

Such a change of the data length may be generated as needed in theprocess of transmitting and receiving data after the Bluetoothconnection.

For example, when the amount of data becomes large in the process oftransmitting data by the first device 300 and the second device 400 byusing Bluetooth LE technology, the data length may be extended through adata length change procedure.

However, when the amount of data, which is transmitted and received bythe first device 300 and the second device 400, is reduced, the datapacket of a long length may increase a bit error rate.

Hence, in such a case, the data packet length may be reduced through thedata length change procedure.

FIGS. 19 and 20 are diagrams showing a process for extending a packetlength after Bluetooth connection and a packet format thereabout towhich the present invention is applied.

Referring to FIGS. 19 and 20, non-connected devices are connected byusing Bluetooth LE technology, then the packet length may be adjusted bynegotiation on the packet length.

Specifically, the first device 300 and the second device 400 initiallyexist in non-connected state which is not mutually connected (S1900).

At this time, when the Bluetooth module of the first device 300 isactivated, the first device 300 transmits an advertisement message orframe including information of the first device 300 itself, to thesecond device 400 for Bluetooth connection (S1910).

When the device that is intended to be connected by the first device 300is correct, the second device 400, which has received the advertisementmessage or frame, requests a connection request to the first device 300for Bluetooth connection (S1920).

The connection request is a message for performing a connectionprocedure with the slave device by the master device in a non-connectedstate, and at this time, all schedule parameter values, which are usedin the connection state as below, may be set.

-   -   Transmit Window Size: It means the length of the section where        actual data may be transmitted and received within a single        connect interval, and at least one packet needs to be certainly        transmitted or received.    -   Window_offset: Offset until actual transmit window is started        within connect interval.    -   Connect Interval: Interval between connect events.

The first device 300, which has received the connection request, triesBluetooth connection by setting the schedule parameter value with thesecond device 400, and when connected, the first device 300 and thesecond device 400 become in a connected state (S1930).

The first device 300 and the second device 400 in the connected statemay transmit and receive data, request or provide certain controlinformation through a control packet, or direct a specific operation.

In the connected state, in Bluetooth LE technology, generally a shortdata packet is used. Hence, in order to use an extended packet, one ofthe two devices may request data packet extension, and before that, theopponent device needs to check whether the extended data packet issupported.

Hence, the first device 300 and the second device 400 may transmit afeature request in order to check whether the extended data packet issupported (S1940).

The second device 400, which has received the feature request, mayinform the first device 300 of whether the extended data packet issupported, through the feature response (S1950).

When the second device 400 supports the extended data packet, the firstdevice 300 requests a length extension to the second device 400 in orderto extend the data packet (S1960).

The length extension request 2010 may include Op code field and CtrDatafield, and the Op code may has the value of “0x14” of the above Table 2.

The CtrData field may include MaxRxLen field, MaxRxTime field, MaxTxLenfield, and MaxTxTime field.

The MaxRxLen field includes the length information of the maximumreceiving data packet which may be supported by the first device 300,and the length of the maximum data packet may be expressed as octetvalue.

The MaxRxtime field includes the transmission time information of themaximum receiving data packet which may be supported by the first device300.

The MaxTxLen field includes length information of the maximumtransmission data packet which may be supported by the first device 300,and the length of the maximum data packet may be expressed as octetvalue.

The MaxTxTime field includes transmission time information of themaximum transmission data packet which may be supported by the firstdevice 300.

The second device 400, which has received the length extension request2010, transmits a length extension response to the first device 300(S1970).

The length extension response has the same format as that of the lengthextension request, and in this case, Op code may have the value of“0x15” of the above Table 2.

The first device 300 and the second device 400 may obtain the maximumdata packet information which may be supported by the opponent device,through the length extension request 2010 and the length extensionresponse and may negotiate the extended packet length and time.

The first device 300 and the second device 400 determines the minimumvalue among lengths of the transmission and reception data packets whichmay be supported by the second device 400 itself and the opponentdevice, as the length of the extended transmission and reception packetby negotiation, and determines the minimum value among data transmissionand reception times, which may be supported by the second device 400itself and the opponent device, as the extended data transmission andreception time by negotiation.

Thereafter, when the length of the determined, extended data packetcannot be transmitted and received within the transmit window size whichhas been set through the connection request, the first device 300 maytransmit a window size update request to the second device 400 in orderto change the transmit window size (S1980).

The window size update request 2020 includes Op code field and CtrDatafield, and in this case, the Op code may have the value of “0x16”.

The CtrData field may include window size field and connect intervalfield.

The window size includes window size information which is intended to bechanged in order to transmit and receive the extended packet, and theconnect interval field may include interval information between theconnect events for the changed window size.

The second device 400, which has received the window size updaterequest, transmits a response thereto to the first device 300 so as toperform window size update (S1990).

After the data packet length is extended, the first device 300 and thesecond device 400 may extend or reduce the data packet length throughthe maximum data length change procedure of FIG. 17 when the data packetlength needs to be changed.

Through such a method, even after Bluetooth connection, the length ofthe data packet may be extended or changed, and the change of theschedule parameter according to length extension of the data packet isalso possible.

Further, by changing the length of the data packet according to theamount of transmitted and received data, when a large amount of data istransmitted, the number of times of transmission and transmission timeof the data packet may be reduced by extending the packet length, andthereby power consumption may also be reduced.

Further, even when the amount of transmitted and received data isreduced after extension of the data packet, the length of the datapacket may be reduced again, and thus the length of the data packetaccording to the situation may be flexibly changed.

The above embodiments include various aspects of examples. Although allpossible combinations for describing the various aspects may not bedescribed, those skilled in the art may appreciate that othercombinations are possible. Accordingly, the present invention should beconstrued as including all other replacements, modifications, andchanges which fall within the scope of the claims.

1. A method of extending a data length of Bluetooth communication by afirst device in a wireless communication system, the method comprising:receiving a first message including information of a second device fromthe second device; transmitting a connection request message to thesecond device based on the first message; performing Bluetoothconnection with the second device based on the connection requestmessage; transmitting an extension request message which requestsextension of a transmission data length and a reception data lengththrough the connected Bluetooth; and receiving an extension responsemessage in response to the request message through the connectedBluetooth, wherein the extension request message includes at least oneof first maximum transmission data length information, first maximumreception data length information, first maximum transmission timeinformation, or first maximum reception time information of the firstdevice, and wherein the extension response message includes at least oneof second maximum transmission data length information, second maximumreception data length information, second maximum transmission timeinformation, or second maximum reception time information of the seconddevice.
 2. The method of claim 1, further comprising: negotiating thetransmission data length and the reception data length with the seconddevice, wherein the transmission data length is negotiated based on atleast one of third maximum transmission data length information or thirdmaximum transmission time information, and wherein the reception datalength is negotiated based on at least one of third maximum receptiondata length information or third maximum reception time information. 3.The method of claim 2, wherein third maximum transmission data lengthinformation is determined by negotiation as a smaller value among thefirst maximum transmission data length information and the secondmaximum reception data length information, wherein the third maximumtransmission time information is determined by negotiation as a smallervalue among the first maximum transmission time information and thesecond maximum reception time information, wherein the third maximumreception data length information is determined by negotiation as asmaller value among the first maximum reception data length informationand the second maximum transmission data length information, and whereinthe third maximum reception time information is determined bynegotiation as a smaller value among the maximum reception timeinformation and the second maximum transmission time information.
 4. Themethod of claim 1, wherein the connection request message includes atleast one of window size information, window offset information, orconnect interval information.
 5. The method of claim 1, furthercomprising: transmitting a window size update request message forchanging a window size; and receiving a response message in response tothe window size update request message.
 6. A method of changing a datalength of Bluetooth communication by a first device in a wirelesscommunication system, the method comprising: receiving first informationrelated with whether extension of a transmission data length and areception data length is supported, from a second device; receivingsecond information related with a data length of the second device fromthe second device; negotiating the data length based on the secondinformation and third information related with a data length of thefirst device; and transmitting the negotiated data length to the seconddevice, wherein the second information includes at least one of firstmaximum transmission data length information, first maximum receptiondata length information, first maximum transmission time information, orfirst maximum reception time information, and wherein the thirdinformation includes at least one of second maximum transmission datalength information, second maximum transmission time information, orsecond maximum reception time information.
 7. The method of claim 6,wherein the negotiated data length includes at least one of atransmission data length, a reception data length, transmission time, orreception time.
 8. The method of claim 7, wherein the transmission datalength indicates a smaller value among the second maximum transmissiondata length information and the first maximum reception data lengthinformation, wherein the reception data length indicates a smaller valueamong the second maximum reception data length information and the firstmaximum transmission data length information, wherein the transmissiontime indicates the second maximum transmission time information and thefirst maximum reception time information, and wherein the reception timeindicates a smaller value among the second maximum reception timeinformation and the first maximum transmission time information.
 9. Themethod of claim 6, wherein the first information and the secondinformation are included in one message so as to be simultaneouslytransmitted.
 10. The method of claim 6, further comprising: transmittinga request message which requests the second information.
 11. The methodof claim 6, further comprising: transmitting a change request messagewhich requests a change of the negotiated data length; and receiving achange request response message in response to the change requestmessage.
 12. The method of claim 11, wherein the change request messageincludes at least one of first reception data length information orfirst transmission data information, and wherein the change responsemessage includes at least one of response information related withwhether the change request is allowed, second reception data lengthinformation, or second transmission data length information.
 13. Themethod of claim 12, wherein the second reception data length informationis determined based on the first reception data length information, andwherein the second transmission data length information is determinedbased on the first transmission data length information.
 14. Anapparatus for extending a data length of Bluetooth communicationincluding a first device in a wireless communication system, wherein thefirst device comprises: a communication unit for transmitting andreceiving a signal in a wired way and/or in a wireless way with anexternal side; and a controller functionally connected to thecommunication unit, wherein the controller: receives a first messageincluding information of a second device from the second device,transmits a connection request message to the second device based on thefirst message, performs Bluetooth connection with the second devicebased on the connection request message, transmits an extension requestmessage which requests extension of a transmission data length, and areception data length through the connected Bluetooth, and receives anextended response message in response to the request message through theconnected Bluetooth, wherein the extension request message includes atleast one of first maximum transmission data length information, firstmaximum reception data length information, first maximum transmissiontime information, or first maximum reception time information of thefirst device, and wherein the extension response message includes atleast one of second maximum transmission data length information, secondmaximum reception data length information, second maximum transmissiontime information, or second maximum reception time information of thesecond device.
 15. The apparatus of claim 14, wherein the controllernegotiates a transmission data length and a reception data length,wherein the transmission data length is negotiated with the seconddevice based on at least one of third maximum transmission data lengthinformation or third maximum transmission time information, and whereinthe reception data length is negotiated based on at least one of thirdmaximum reception data length or third maximum reception timeinformation.
 16. The apparatus of claim 15, wherein third maximumtransmission data length information is determined by negotiation as asmaller value among the first maximum transmission data lengthinformation and the second maximum reception data length information,wherein the third maximum transmission time information is determined bynegotiation as a smaller value among the first maximum transmission timeinformation and the second maximum reception time information, whereinthe third maximum reception data length information is determined bynegotiation as a smaller value among the first maximum reception datalength information and the second maximum transmission data lengthinformation, and wherein the third maximum reception time information isdetermined by negotiation as a smaller value among the maximum receptiontime information and the second maximum transmission time information.17. The apparatus of claim 14, wherein the connection request messageincludes at least one of window size information, window offsetinformation, or connect interval information.
 18. The apparatus of claim14, wherein the controller transmits a window size update requestmessage for changing a window size and receives a response message inresponse to the window size update request message.
 19. (canceled)